160 Proceedings of Royal Society of Edinburgh. [sess. 
end of which a writing style was attached. A record was made on 
a revolving drum. By this means, and by an electric marker which 
marked half minutes, the rate of flow was graphically represented. 
The solutions were, in all cases, made with Locke’s modification 
of Ringer’s solution. It was found necessary to make the solution 
immediately before use, as the fluid became pink, and rapidly 
lost its activity. 
1. Perfusion of the Vessels in the Pithed Frog . — Perfusion of 
1 per million gives a very marked constriction, which continues 
for a considerable time after the adrenalin is withdrawn and 
Locke’s solution is again perfused. Recovery, however, takes 
place (unless the constricting fluid has been perfused for too 
long a time), and the normal rate is re-established. Further 
dilution to 0*5 per million gives a considerable constriction, 
while there is still a feeble reaction with a solution of *1 in one 
million. 
The following experiment shows the slight constricting action 
of 0*1 per million : — 
After perfusion for some time. 
Solution. 
Time. 
Drops per minute. 
3*50 
24 
Locke’s solution. 
3*53 
24 
3*56 
24 
3-58 
Adrenalin 0*01 per cent, of 
1 in 1000, 0*1 in a million. 
4*1 
20 
4*2 
21 
1 
4-3 
20 
4-4 
20 
4*5 
20 
4-8 
20 
Locke’s solution. 
4*11 
20 
4*14 
22 
4'16 
23 
4*17 
22 
4-18 
24 
When this result is compared with Lawen’s, a great similarity 
is seen. 
He got marked constriction with *002 mg. in 10 c.c. suprarenin, 
i.e. with 0*2 per million. 
